SONOS, short for "silicon–oxide–nitride–oxide–silicon", more precisely, "polycrystalline silicon"—"silicon dioxide"—"silicon nitride"—"silicon dioxide"—"silicon",[1]: 121 is a cross sectional structure of MOSFET (metal–oxide–semiconductor field-effect transistor), realized by P.C.Y. Chen of Fairchild Camera and Instrument in 1977.[2] This structure is often used for non-volatile memories, such as EEPROM and flash memories. It is sometimes used for TFT LCD displays.[3] It is one of CTF (charge trap flash) variants. It is distinguished from traditional non-volatile memory structures by the use of silicon nitride (Si3N4 or Si9N10) instead of "polysilicon-based FG (floating-gate)" for the charge storage material.[4]: Fig. 1 A further variant is "SHINOS" ("silicon"—"hi-k"—"nitride"—"oxide"—"silicon"), which is substituted top oxide layer with high-κ material. Another advanced variant is "MONOS" ("metal–oxide–nitride–oxide–silicon").[5]: 137 [6]: 66 Companies offering SONOS-based products include Cypress Semiconductor, Macronix, Toshiba, United Microelectronics Corporation and Floadia Archived 2022-11-01 at the Wayback Machine.
Chen 1997
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